Polyoxyalkylene-containing ammonium compounds



United States Patent 3,428,682 POLYOXYALKYLENE-CONTAINING AMMONIUM COMPOUNDS Richard R. Egan, Edina, and Leon D. Smiens, Minneapolis, Minn., assignors to Ashland Oil & Refining Company, Ashland, Ky., a corporation of Kentucky N0 Drawing. Filed June 6, 1966, Ser. No. 555,264 U.S. Cl. 260-567.6 Claims Int. Cl. D06m 15/12; C07c 93/04; D06c 19/00 ABSTRACT OF THE DISCLOSURE Quaternary amonium compounds, useful in fabric softeners, are prepared by quaternizing tertiary amines of the general formula R (R )N(R O),,H, where R and R are aliphatic hydrocarbon radicals and R 0 is a heteric polyoxyalkylene chain, with an alkyl halide, acid, or the like.

This invention relates to polyoxyalkylene-containing quaternary ammonium compounds and to liquid fabric softeners prepared from the novel polyoxyalkylene-containing quaternary ammonium compounds.

With the development of automatic washing machines for both commercial and home use, and with the development of synthetic detergents, fabric softener formulations, which are generally added to the rinse cycle of an automatic washing process, have become increasingly more important and widely used. Fabrics washed by the described automatic process without use of a fabric softener formulation tend to exhibit a surface hardening and are stiffer and harsher to the touch than the unwashed material. The addition of a fabric softener formulation is intended to overcome this undesirable effect and results in a softer, fiuffier fabric on washing and drying. These fabric softener formulations comprise a diluent, e.g., water in the case of a liquid formulation, and an active compound which has the function of actually softening the fabric. Liquid fabric softener formulations have been far more widely accepted by consumers than solid formulations. In any case, to be truly useful in a fabric softener formulation, the active compound must have a combination of properties of which its ability to soften fabrics is only one. Another critical feature of the active fabric softener is its solubility characteristics in water: it is important that the active fabric softener be quickly and uniformly distributed throughout the laundry water and that it dissolves or colloidally disperses rapidly therein. In the case of liquid formulations, it must be able to similarly dissolve in the liquid formulation diluent. Compounds which are liquids or can be readily dissolved or colloidally dispersed in a liquid diluent to form a liquid concentrate that can be further diluted to form the ultimate liquid fabric softener formulation are commercially attractive because of ease of storage and handling. Also, it is generally necessary to use the active compound in the form of a liquid concentrate when manufacturing the liquid fabric softener formulation for the ultimate c0nsumer. Normally fabric softener concentrations Which contain concentrations of the active component of less than 70% are commercially unattractive.

It is an object of this invention to provide novel polyoxyalkylene-containing quaternary ammonium compounds.

It is another object of this invention to provide liquid fabric softener formulations, the active component being the novel polyoxyalkylene-containing quaternary ammonium compounds of this invention.

It is still another object of this invention to provide a process for preparing the novel polyoxyalkylene-containing quaternary ammonium compounds.

Other objects will become apparent from the following disclosure and claims.

The novel quaternary ammonium compounds of the present invention have the general formula:

in which R and R are aliphatic hydrocarbon radicals of 12 to 20 carbon atoms, and where R and R can be the same or different radicals in each instance; R 0 is a heteric polyoxyalkylene chain of randomly distributed oxyethylene and oxypropylene units, It is an integer equal to the total number of oxyalkylene units in the chain and is from 3 to 12, and preferably from 4- to 7, the ratio of oxyethylene to oxypropylene units in said chain varying from 1.5 to 4, and preferably from 2 to 3; R is hydrogen or a lower alkyl (C -C radical, and X is an anion.

The polyoxyalkylene-containing quaternary ammonium compounds of the present invention are obtained by the quaternization of tertiary amines produced by the condensation of a mixture of ethylene oxide and propylene oxide with a secondary amine containing two aliphatic hydrocarbon radicals. It is well recognized in the field of alkylene oxide chemistry that the oxyalkylation of a reactive hydrogen-containing compound with excess alkylene oxide results in the formation of a polymer of the alkylene oxide containing a terminal hydroxyl group. The reaction does not result in a single molecular compound having a defined number of oxyalkylene radicals, but rather one obtains a mixture of closely related homologs wherein the statistical average number of oxyalkylene groups equals the number of moles of the alkylene oxide employed per mole of reactive hydrogen compound and the individual members present in the mixture contain varying numbers of oxyalkylene groups. Where, as in this invention, different oxyalkylene groups are distributed randomly throughout the oxyalkylene chain, and thus, in addition to the varying lengths of the polyoxyalkylene chain, result in a varying structure of the oxyalkylene chain, it is conventional to characterize the chain as a heteric polyoxyalkylene chain. Nevertheless, the properties of the compounds containing such polyoxyalkylene chains is characterized by the average length of the polyoxyalkylene chain and the average ratio of oxyethylene to oxypropylene units in the polyoxyalkylene chain.

The novel polyoxyalkylene-containing quaternary ammonium compounds of the present invention are produced by a process which comprises the quaternization of a tertiary amine having the general formula:

(II) l tz R1 N \RsO/n in which R R and R 0 have the above-indicated meaning. The tertiary amines employed in this process are obtained by the condensation of a secondary amine containing two aliphatic hydrocarbon radicals of 12 to 20 carbon atoms with a mixture of ethylene oxide and propylene oxide at temperatures of F. to 280 F. in the presence of an ionic alkaline catalyst such as the salts or the hydroxides of the alkali metals or the alkaline earth metals and preferably in the presence of a lower alkyl (C -C secondary alcohol such as isopropanol which acts as a color formation inhibitor. Since an essen tially complete reaction between the secondary amine and the amine and the alkylene oxide is obtained, the average chain length of the polyoxyalkylene chain in the tertiary amine is readily controlled by the molar proportions of the alkylene oxide to the secondary amine reacted with each other. Similarly, the average oxyethylene-tooxypropylene ratio in the polyoxyalkylene chain is controlled by the molar ratio of the ethylene oxide to propylene oxide in the mixture charged to the secondary amine. The preparation of the tertiary amines is described in greater detail in cofiled copending application Ser. No. 555,265. The quaternization of the tertiary amine is carried out by reacting the tertiary amine With a compound having the formula R X wherein X is the anion desired in the quaternary ammonium salt, and R is a lower alkyl radical or hydrogen at a temperature of about 150 F. to about 220 F. The preferred quaternizing agents are alkyl chlorides, alkyl bromides, dialkyl sulfates, dialkyl sulfonates, and alkyl aryl sulfonates in which the alkyl groups have from 1 to 4 carbon atoms and more preferably in which the alkyl groups are methyl. Other preferred quaternization agents include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and monocarboxylic organic acids having from 1 to 3 carbon atoms.

In the quaternization of the tertiary amine with an R X compound wherein R is a lower alkyl group of l to 4 carbon atoms, the quaternization is conducted by charging the tertiary amine to a reactor without any diluent added or with sufllcient diluent added to result in a liquid solution having the desired activity in the application of the resulting quaternary ammonium compound. In addition to the diluent, there is charged a neutralizing agent to neutralize any free acid formed as a result of the reaction. The mixture is heated to the desired temperature at which the reaction proceeds at a desired rapid rate without decomposition of the quaternary product (which de sired temperature will generally be within the range of 150 to 220 F.) and the quaternizing agent, which is normally gaseous at the reaction condition, is charged to the reaction mixture at pressures ranging from autogenous to 200 p.s.i.g., although such pressure is not critical. The quaternizing agent is charged in excess of 50 to 100% of the stoichiometric quantity required to form the quaternary ammonium compound and can be added as a single charge or in increments as desired. With certain quaternizing agents, some decomposition of the quaternizing agent can occur during the reaction and it may, therefore, be desirable to repeatedly vent and recharge the reaction vessel with the quaternizing agent until no further reaction occurs, as established by pressure drop. In the quaternization of the tertiary amines with an inorganic or organic acid, a stoichiometric amount of the acid, as determined by titration of a sample of the tertia y amine, is added to the tertiary amine. The acid can be employed in concentrated or diluted form. The tertiary amine reagent employed in the quaternization can be employed without purification when formed by the above-described process, or, if desired, can be employed in pure form. The optionally employed diluents are water, water-miscible organic solvents such as lower alkanols and mixtures of water and such organic solvents. The diluent, where used, can be from to 50 weight percent, or higher, based on the final total reaction mixturerwhere such diluent is used, the resulting quartenary ammonium product is obtained as a normally liquid material (with freezing point below 65 F.) which can be employed as a concentrate to make fabric softener formulations. If desired, the concentrate can be filtered to remove inorganic salt residue. If desirable, acid or a base can be added to adjust the pH of the product to within a range of 6 to 9. In instances where a diluent is not used in the preparation of the quaternary ammonium product, the latter will be a solid or soft paste at room temperature, and it is preferred to add said diluent in order to obtain a liquid product. For reasons discussed above, a liquid product is preferred in preparing fabric softener formulations.

The quaternary ammonium compounds of the present invention are surface-active agents which exhibit a particular combination of properties making them eminently suitable as active components in fabric softener formulations. In liquid fabric softener formulations (the preferred utility of the quaternary product of this invention), the active component will be from 3 to 10 weight percent of the formulation, and preferably about 5 weight percent. However, said quaternary compounds can beadmixed with inert solid diluents, such as sodium sulfate, sodium chloride, urea, etc., to form solid or particulate fabric softener formulations, having for example 15 to 20 weight percent of active component.

Although quaternary ammonium compounds containing two aliphatic hydrocarbon radicals of 12 to 20 carbon atoms are known to have superior fabric-softening properties, the solubility and physical characteristics of the compounds have adversely affected the useof such quaternary ammonium compounds as fabric softeners. It was surprisingly found that by incorporating a polyoxyalkylene chain of particular configuration into the quaternary ammonium compound the disadvantages of prior art quaternary ammonium compounds in their utility as fabric softeners could be reduced or eliminated. Thus, quaternary ammonium compounds containing a heteric polyaxyalkylene chain of 3 to 12 and preferably of 4 to 7 randomly distributed oxyethylene and oxypropylene units wherein the average oxyethylene-to-oxypropylene ratio is from 1.5 to 4 and preferably from 2. to 3, are liquid in concentrates containing or less of the quaternary ammonium compounds. These compounds and their concentrate dissolve or colloidally disperse readily in water, even in cold water. The compounds significantly improve the hand and feel of fabrics on washing and drying with automatic equipment. Fabrics softened with these compounds have improved rewettability properties and liquid fabric softener formulations based on these compounds have superior freeze-thaw stability as compared to such known liquid fabric softener formulations based on dimethyl-di(hydrogenated tallow) ammonium chloride. The particular structure of the polyoxyalkylene chain is critical in achieving the described improved properties. Thus, both an increase or a decrease in the average chain length of the polyoxyalkylene causes increased tendency to solidify at the required concentrate levels. Both ethylene oxide and propylene oxide are necessary, as is the randomness of the distribution of the alkylene oxide units in the polymer chain. The use of only ethylene oxide results in products which are largely solids or mixtures of liquid and solids in the concentrates, While the use of solely propylene oxide causes the product to have less solubility. Block copolymer chains are undesirable since quaternary ammonium compounds containing such reflect the properties attributable to a polyoxyethylene chain and a polyoxypropylene chain which, as explained above, are undesirable, rather than a novel combination of properties obtainable by random copolymerization. It will be apparent that optimum combinations of properties desirable in a fabric softener will also vary with the nature of the aliphatic hydrocarbon radical having from 12 to 20 carbon atoms, and that such can be compensated for by adjusting the average length of the polyoxyalkylene chain and/or the average oxyethylene-to-oxypropylene ratio within the operative ranges set forth hereinabove. The solubility is, additionally, affected by the radical attached to the nitrogen atom as a result of the quaternization. In general, the solubility of the quaternary ammonium compound decreases as the number of carbon atoms in the added radical is increased and hence it is preferred that the radical added through quaternization is either hydrogen or methyl. It is to be understood, however, that the utility of the quaternary ammonium compound of the present invention is not limited to the described fabric softeners and that in view of their surface activity, the quaternary ammonium compounds of the present invention can be employed in a wide variety of detergent applications.

The aliphatic hydrocarbon radicals attached to the nitrogen of the quaternary ammonium compounds are aliphatic hydrocarbon radicals of 12 to 20 and preferably of 14 to 18 carbon atoms, which are preferably free of ethylenic unsaturation. The hydrocarbon radical need not be the same in each molecule and can also vary from molecule to molecule within the described range. A particularly preferred hydrocarbon radical is the hydrogenated tallow radical which itself is a mixture of C to C fatty radicals. When preparing quaternary ammonium compounds based on di(hydrogenated tallow) amine, the optimum properties for a fabric softener are realized with polyoxyalkylene chains of about 7 oxyalkylene units at a oxyethylene-to-oxypropylene ratio of 4: 1.5.

The invention is further illustrated by the following examples in which, unless otherwise stated, all units of quantity are by weight.

EXAMPLE 1 Into a stainless steel autoclave is charged 653 g. of a di(hydrogenated tallow)polyoxyalkylene amine containing an average of 4 ethylene oxide and propylene oxide units in the polyoxyalkylene chain, the average oxyethylene-to-oxypropylene ratio in the chain being 3:1, 235 g. of an isopropanol water mixture containing 4 parts of isopropanol and 1 part of water, and 60 g. of sodium bicarbonate. The reaction mixture is heated to a temperature of 212 F. and pressured to 40 to 60 p.s.i.g. with methyl chloride. On reaching equilibrium conditions, the reaction gases are vented. Recharging and venting of the reaction mixture is repeated until no further methyl chloride is absorbed by the reaction mixture. The resulting product is filtered and a solution containing 75 of the resulting quaternary ammonium compound, di(hydrogenated tallow)-polyoxy(ethylene-propylene) methyl ammonium chloride, is obtained.

EXAMPLE 2 The procedure of Example 1 is repeated employing ethyl bromide in place of the methyl chloride and upon filtering a liquid solution containing 75% of di(hydrogenated tallow)polyoxy(ethylene-propylene) ethyl ammonium bromide is obtained.

EXAMPLE 3 The procedure of Example 1 is repeated except that a 100% excess, based on the stoichiometric quantity of quaternizing agent required for the amine, of methyl chloride is charged to the reaction vessel initially and the reaction vessel is agitated at autogenous pressure for a period of three hours at 100 F. On filtering, there is obtained at 75% liquid concentrate of di(hydrogenated tallow)-polyoxy(ethylenepropylene) methyl ammonium chloride.

EXAMPLES 4-7 A number of di(hydrogenated tallow)-polyoxy(ethylenepropylene) methyl ammonium chloride compositions having in the polyoxy(ethylene-propylene) chain the average chain lengths and oxyethylene-to-oxypropylene ratios indicated in the following table are prepared by the procedure of Example 1. The characteristic properties and impurities of the compositions are set forth in the table.

tablish the effectiveness of the fabric softener. The soft ness of the towels was measured on an arbitrary scale of 1 to 5 in which 5 is the softness obtained by washing and drying the towels by the standard cycle in the absence of any fabric softener and 1 is the softness of the unwashed towels employed in the test. The softness rating is based on an average of at least 5 measurements of each of five different persons having no knowledge of the washing and drying history of the towels. The rewettability is established by measuring the time required for the towel to absorb a given weight of water and is based on an average of four readings. The table below shows the fabric softeners of the present invention to have a superior combination of properties.

quaternary ammonium compound. Commercially available -O.1

imidazoline compound.

! Based on weight of fabric.

The foregoing examples have illustrated the preparation, properties, and utility of the novel quaternary ammonium compounds of the present invention. As: will be apparent from these examples, other tertiary amines falling within the scope of the invention and other alkyl compounds and acids can be employed in the specific procedures illustrated to produce the described quaternary ammonium compounds. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should, therefore be understood that the foregoing description and examples are not to be construed as limiting.

What is claimed is:

1. A compound having the formula:

wherein R and R are alkyls of 12 to 20 carbon atoms, said alkyls being the same or different; R 0 is a heteric polyoxyalkylene chain of randomly distributed oxyethylene and oxypropylene units, said chain having from 3 to 12 units, the ratio of oxyethylene to oxypropylene units being from 1.5/1 to 4/1; R is hydrogen or an alkyl group of l to 4 carbon atoms; and X is an anion selected from the group consisting of chloride, bromide,

TAB LE 1 Composition Impurities Percent Diluents based on mixture Properties Ex. Number of EO/PO Percent Percent Percent Percent Percent Cloud Gardner State after 24 oxyalkylene ratio AH 1 FA 2 Hi0 MeOH i-PrOH point F.) color hrs. at room units temperature 4 3 Trace 1. 9 3 22 3+ Clear liquid. 4. 5 2 -do. 2. 1 3 22 67 4 Do. 5. 5 2. 67 do. 1. 4 112 4 Soft paste. 5. 5 2. 67 --do 1. 4 2 18 64 4 Clear liquid.

l Amine hydrochloride resulting from quaternization of unreacted secondary amine.

I Unreacted secondary and tertiary amine.

In the following table, the use of some of the quaternary ammonium compounds described in Table 1 as fabric softeners is illustrated. The samples were employed at the concentration indicated in the rinse water of a standard automatic washing and drying cycle using towels to essulfide, phosphate, alkanoate of from 1 to 3 carbon atoms, methyl sulfate and sulfonate.

2. The compound of claim 1, wherein the chain has from 4 to 7 units and the ratio of oxyethylene to oxypropylene is from 2 to 3.

3. The compound of claim 1, wherein R is methyl.

4. The compound of claim 1, wherein X is chlorine, bromine, methyl sulfate, or alkanoate of from 1 to 3 carbon atoms.

5. The compound of claim 1, wherein R and R are di'hydrogenated tallow radicals.

6. The compound of claim 5, wherein the polyoxyalkylene chain contains from 3 to 7 units, the ratio of oxyethylene to oxypropylene is from 2 to 3, and R is methyl.

7. The compound of claim 1 where R and R are dihydrogenated tallow radicals, R is methyl, X is chloride, and R 0 is a polyoxyalkylene chain having 3 to 7 units, the ratio of oxyethylene to oxypropylene being from 2/1 to 3/1.

References Cited UNITED STATES PATENTS LEON ZITVER, Primary Examiner.

10 L. C. MARUZO, Assistant Examiner.

US. Cl. X.R. 

